Ferrous alloys and abrasive-resistant articles made therefrom



Patented Nov. 13, 1951 FERROUS ALLOYS AND ABRASIVE-RESIST- ANT ARTICLES MADE THEREFROM David J. Giles, Latrobe, Pa., assignor to Latrobe Electric Steel Company, Latrobe, Pa., a corporation of Pennsylvania No Drawing. Application July 28, 1950,

Serial No. 176,533

This invention relates to ferrous alloys and in particular to non-deforming ferrous alloys having high resistance to abrasion. There has long been a demand for a ferrous alloy which can be either cast or forged with exactness as to form and dimension and oil-hardened after machining, which alloy would have high resistance to abrasion and would take a high surface finish. Such a ferrous alloy is particularly needed for the production of master tools and gauges special taps and broaches, ball bearings and the like and for dies that cannot be ground after hardening or that are of a design which is likely to cause them to crack if water-quenched. In particular, such a ferrous alloy is of great advantage in the fabrication of blanking dies and cold forming dies for stamping sheet steel. Dies of this type are formed and machined prior to hardening and must retain their shape and dimension during and after the hardening process. Moreover, when used for stamping sheet steel, either ordinary or stainless they are constantly subjected to abrasion causing them to wear away more or less rapidly thereby losing their criticality of dimension and shape beyond acceptable tolerances.

An alloy, to be suitable for use in manufacturing articles such as are described above, must necessarily be forgeable or castable in intricate shapes, in most cases machinable, and hardenable without unduly deiormingorshrinking'after the hardening treatment and yet be resistant to the abrasive action of the materials upon which they are used.

Non-deformin steels presently used in theart usually contain about .90% to 1% carbon and 1 manganese, along with small amounts of other alloying constituents, some of which are residual elements carried from the raw materials and other of which are added for some desirable property which they impart to the steel. For example, vanadium to 25% is frequently added to such non-deforming steels to retard graingrowth, and tungsten and chromium in the vicinity of 50% are for added hardenability and uniformity of response to heat treatment- Larger quantities of vanadium than 25% have been avoided and have heretofore been deemedof no advantage to this type of steel.

I have discovered an alloy which is non-de- I 15 Claims. (Cl. 75-123) a result of properly controlling the carbon and vanadium content in a manner hereafter to be described. My invention provides an alloy in which carbon within certain limits is added in excess of that necessary to give the alloy the desired forging and hardening characteristics, and in which vanadium is added in an amount, again within certain limits, such that the ratio of the vanadium in excess of about 1% to the aforementioned excess of carbon is about 4. 2:1. H

The alloy of this invention may have the following broad general analysis:

Per cent Carbon 1 to 3.75 Vanadium l 2 to 13 At least one of the group consisting of chromium, tungsten, manganese and molybdenum in individual percentages of:

Per cent Manganese .9 to 2.5 Chromium 1.4 to 5 Tungsten 1.75 to 6.5 Molybdenum 1 to 4 and in aggregate percentages in substituted amounts such that the hardening properties produced by the aggregate are substantially equal to the hardening properties produced by any individual member of the group within its individual percentage range. Balance substantially iron with residual impurities in ordinary amounts.

I have found that the abrasion resistance of my alloy varies with the amounts of vanadium and carbon so that an alloy having an abrasion resistance and other properties intermediate the two extremes characteristic of the broad analysis stated above might have the following specific analysis:

- Per cent Carbon 1.7 Vanadium 4.5

At least one of the group. consisting of chromium, tungsten, manganese and molybdenum in individual percentages of:

Per cent Manganese 1.5 Chromium 3.0 Tungsten 3.2 Molybdenum 1.9

and in aggregate percentages in substituted amounts such that the hardening properties produoed by the aggregate are substantially equal to the hardening properties produced by any individual member of the group withinits individual percentage range. Balance substantially iron with residual impurites in ordinary amounts.

The use of any particular member or combination of members from the aforesaid group of manganese, chromium, tungsten and molybdenum is not mandatory so long as at least one member of the'group appears in the amounts given above. The member which is used may be selected on the basis of what properties other than resistance to deformation, resistance to abrasion and oil hardenability are desired to be accentuated in the alloy. For example, a particularly desirable consisting of chromium, tungsten, manganese, and molybdenum in certain individual percentages and in aggregate percentages in substituted amounts such that the hardening properties produced by the aggregate are substantially equal to the hardening properties produced by any individual member of the group within its individual percentage range. By this latter statement I mean that any or all of the group chromium, tungsten, manganese, and molybdenum may appear in the alloy providing that in the aggregate the percentage of each is so limited that the hardening properties which the aggregate produces in the resulting alloy are substantially equal to the hardening properties which would be produced in the same alloy by any one of the group taken alone within the individual percentage limitations set forth above.

I have stated that the balance is substantially iron with residual impurities in ordinary amounts. By residual impurities in ordinary amounts I mean in those amounts which will ordinarily be added to the alloy in the raw materials. For example, I have found that the silicon percentage may at times go as high as 50% in my alloy depending upon the silicon content of the ferroalloys and the steel scrap from which the alloy is melted. In such instances the impurities are not added for their effect upon the steel but are merely an unavoidable concomitant to large ferroalloy sgap additions.

It is important to note that to achieve the phenomenal abrasion resistance of my invention yet retain the desired forging, hardening and non-deforming characteristics, it is necessary that the carbon and vanadium contents be carefully controlled within the teaching of thisspeciflea-tion. It is necessary that the carbon in excess of that required to give the forging and hardening characteristics desired appear in the alloy along with vanadium in excess of 1% in the ratio of 4.2 vanadium to 1 carbon.

The importance of my present alloy to the art and its strikingly new qualities are best illustrated by referring to the following examples in .which the results of abrasion tests on alloys of Table I alloy composition for most general purposes might have the following composition: 15 G d lHargm y Amount An A a 6 1n em- 00 0 Carbon 1 l t oii r pegmture well 0 ofwear y Vanadium 2to 13 c Pedant M n n e .9 to 2.5 AlloyA (Standard) 2350 65.0 .0037 Tungsten Optional to 1 333% Chromium Optional to 1 moi-1D 1 1pm 6310 0006 16 Balance substantially iron with residual impurifig; 1%83 8833 2 ties in ordinary amounts.

If, on the other hand, it is desired to increase Table II the surface'finishing qualities (i. e., ability to take 25 a high polish etc.) of the alloy while still re- Grade 0 si Mn Cr v w Mo taming its resistance to abrasion and deformation, the major part of the manganese and tung .31 .25 4.23 1.09 sten in the alloy above may be replaced by molyb- 11mm .42 1.08 .67 4.65 denum and chromium. .33 .24 .58 4.61 I have stated in my broad general analysis that -23 the composition contains at least one of the group A careful comparison of the above tables shows the marked superiority of the alloys of my invention over both the high-speed steel standard and the alloy (alloy 13) now used for the purposes for which the alloy of this invention is intended. The alloy heretofore used has lost about eight times as much material as the alloy of my invention while the high-speed steel standard has lost more than three times as much material as any alloy according to my invention and twelve times as much as at least one of my alloy compositions tested. It is notable that while the carbon of my alloy compositions has been increased far above the carbon content of the alloy heretofore used there has been little or no effect on the forgeability and hardenability of my alloy over these same properties in the alloy heretofore used. It will be seen from Table 1 that the Rockwell C hardness of alloy B and alloys 0 and D are substantially identical as are their forging qualities. Their abrasion resistance however is markedly different as appears in Table I. It is clear from a study of the compositions of the alloys B and C that these improved characteristics appear with the addition of excess carbon and vanadium in excess of 1% in the ratio of 4.2 vanadium to 1 carbon, since the balance of the two alloys is substantially identical. This marked superiority in resistance to abrasion continues so long as the ratio of 4.2:1 is maintained. If however, a marked departure from this ratio is made then a striking change in forgeability and hardenability occurs, the direction and extent of which depend upon the material and extent of the departure from this ratio.

' While I believe that the extraordinary abrasion resistance of my alloy depends upon the formation of vanadium carbides which remain out of solution and do notaffect the hardenability and forgeability of the alloy I do not bind myself to this theory. I have found that whatever the mechanism may be I am able to achieve a very desirable increase in abrasion resistance without 25 f-mask'ing, inullifying or :otherwise eil'ectirxg the other desirable physical characteristics of (the alloy. "The fact is thahwhatever the mechanism :mayzbe the addition of carbon and vanadium in the proportions described in the specification in conjunction with the proportions of the bther alloying materials making :up the alloy of this invention does produce an :unexpected and unusual resistance tc-abrasion alongwith the desired none-deforming characteristics which :com-

-bination :of properties is 0f .great techn'ical :im- :portance.

While "I have described and disclosed .a :pre- 'ferred embodiment -.of my invention Fit :is to :be

understood that it -.not so :limited-tbut may "be '15 rotherwise practiced and .embodied within the =.-scope of the :following claims.

I claim: 1. An abrasion resisting non-deforming steel alloy having carbon in excess of that necessary molybdenum in individual percentages of manganese .90% to 2.5%, chromium 1.4% to 5%, tungsten 1.75% to-65%, molybdenum 1% to and in a gregate percentages in substituted amounts such 'thatthe hardening properties produced by the aggregate are substantiallyequal to thehardening properties-produced-by anyindividual'member-oithe groupwithin its-individualpen 'centage and the balance substantially iron with residual impurities in ordinary amounts in which 'alloy the concentrations of-vanadium and carbon within the given limits are adjusted so that'theratio of -vanadiumiin excess of about"1% to the excess carbon is about 4:211.

2. An abrasion resisting non-deforming steel alloy having carbon in excess of that necessary to give it the desired hardenability characteristic comprisingabout 1.7% carbon, about 4.5% vanadium, at "least one of the group consisting of chromium, tungsten, manganeseand molybdenum in individual percentages of manganese 1.5%,

chromium 3.0%, tungsten .2%, molybdenum 1.9% and in aggregate percentages in substituted amounts such 'that'the hardening properties produced .by the aggregate aresubstantially equal to .the hardening properties produced by :any indib0 Midual member of the group within its individual ,percentage range, and .the .balance substantially .iron with residual impuritiesin ,ordinaryiamounts in which alloy the concentrations of vanadium and carbon within the givenlimits are adjusted 5.3

so that the ratio of vanadium in excess of about 1% to the excess carbon is about 42:1.

:3. An-abrasion resisting non-deforming article rfolmed from a forgeable abrasion resisting-steel alloy comprising about 1% to 3.75% carbon, about 2% to 13% vanadium, at least one of the group consisting of chromium, tungsten, manganese and molybdenum in individual percentages of manganese .90% to 2.5%, chromium 1.4% to 5%,

tungsten 1.75% to 6.5%, molybdenum 1% to 4% 5 and in aggregate percentages in substituted amounts such that the hardening properties produced by the aggregate are substantially equal to the hardening properties produced by any in- .6 'acteristics comparable to steels having a carbon "content less than thatcf-the article by anamount equal-to about the per cent vanadium -11 .42

4. ,An Qabrasion resisting non-deforming article formed .fromsaforgeable abrasion resistingsteel alloy comprising about 11.77% rcarbon, about 45% vanadium, at least one of the group consisting of chromium, tungsten, manganese and molybdenum in individual percentages of manganese 1.5%, chromium -3;0-%, "tungsten 3.2%, molybdenum 11.9 :and in aggregate percentages in substituted amounts such that the hardening "properties produced by the aggregate are substantially-equal to the hardening properties-produced =by any individual member of the group :within its individual percentage range, and the balance substantially iron with residual impurities in ordinaryamounts, said article being characterized by high resistance to abrasion, resistance to deformation on hardening, and by forging and hardening characteristics comparable to steels having a carbon content less than that of the article by an amount equal to about the per cent vanadium 1 4.2

5. An abrasion resisting non-deforming steel alloy having carbon in excess of that necessary to give it the desiredfhardenability characteristic comprising about 1% to 3.75% carbon, about 0 .9% to 235% manganese, an optional amount to about 1% tungsten, an optional amount to about "1 chromium, the tungsten and chromium being in substitution for an equivalent amount of manganese, about-2% to 13% vana 'dium and the balance substantially iron with residual impurities in ordinary amounts 'in which alloy the concentrations of vanadium and earbon within the given limits are adjusted so that the ratio of vanadium in excess of about 1% to the excess :carbon "is about 4.211.

'6. An a'brasion resisting coon-deforming steel alloy having carbon in excess of that necessary to give it the desired fhardenability characteristic :comprising about 137% carbon, about 1.2% 'manganese,.about..5% tungsten, 5% chromium, 455% vanadium :Gtl'ld the balance substantially .iron with iresidua l impurities iincrdinary amounts in which alloy the concentrations of vanadium and :carbon within "the :given limits :are adjusted 'so that the. ratio of vanadium in excess of about -l'%i.to the excess carbon is about 4.211.

An abrasion resisting non-deforming arti- {G18 iformed "from .a 'forgeable :abrasion resisting steel alloy comprising about 1% to 3.75% carbon, about 0;9% to 25% manganese, an optional amount to about 1% tungsten, an optional amount to about 1% chromium, the tungsten and chromium being in substitution for an equivalent amount of manganese, about 2% to 13% vanadium and the balance substantially iron "with residual impurities in ordinary amounts, said article being characterized by high resistance to abrasion, resistance to deformation on hardening and by forging and hardening characteristics comparable to steels having a carbon content less than that of the article by dividual member of the group within its indian amount equal to about vidual percentage range, and the balance substantially iron with residual impurities in ordinary amounts said article being characterized by high resistance to abrasion, resistance to deformation the per cent vanadium1% 4.2 8. An abrasion resisting non-deforming article on hardening, and by forging and hardening charformed from a forgeable abrasion resisting steel alloy comprising about 1.7% carbon, about 1.2% manganese, about .5% tungsten, about chromium, about 4.5% vanadium and the balance substantially iron with residual impurities in ordinary amounts, said article being characterized by high resistance to abrasion and by forging and hardening characteristics comparable to steels having a carbon content less than that of the article by an amount equal to about the per cent vanadiuml 4.2

9. An abrasive resistant non-deforming stamping die formed from a forgeable abrasion rcsisting steel alloy comprising about 1% to 3.75% carbon, about 0.9% to 2.5% manganese, an optional amount to about 1% tungsten, an optional amount to about 1% chromium, the tungsten and chromium being in substitution for an equivalent amount of manganese, about 2% to 13% vanadium and the balance substantially iron with residual impurities in ordinary amounts, said article being characterized by high resistance to abrasion, resistance to deformation on hardening and by forging and hardening characteristics comparable to steels having a carbon content less than that of the article by an amount equal to about the per cent vanadium l 10. An abrasion resisting non-deforming alloy comprising about 1% to 3.75% carbon, about 2% to 13% vanadium, about 1% to 4% molybdenum, an optional amount to about 3.6% chromium, an optional amount to about 4.75% tungsten, the chromium and tungsten being substituted for an equivalent amount of molybdenum, and the balance substantially iron with residual impurities in ordinary amounts in which alloy the vanadium in excess of about 1% is combined with carbon in a ratio of about 4.221.

11. An abrasion resisting non-deforming article formed from a forgeable abrasion resisting steel alloy comprising about 1 to 3.75% carbon, about 2% to 13% vanadium, about 1% to 4% molybdenum, an optional amount to about 2.5% chromium, an optional amount to about 3.0% tungsten, the chromium and tungsten being substituted for an equivalent amount of molybdenum,

and the balance substantially iron with residual impurities in ordinary amounts, said article being characterized by high resistance to abrasion, resistance to deformation on hardening and by forging and hardening characteristics comparable to steels having a carbon content less than that of the article by an amount equal to about the per cent vanadium-1% 4.2

12. An abrasion resisting non-deforming alloy comprising about 1% to 3.75% carbon, 2% to 13% vanadium, 1.4% to 5% chromium and the balancesubstantially iron with residual impurities in ordinary amounts in which alloy the vanadium in excess of about 1% is combined with carbon in a ratio of about 42:1.

13. An abrasion resisting non-deforming article formed from a forgeable abrasion resisting steel alloy comprising about 1% to 3.75% carbon, 2% to 13% vanadium, 1.4% to 5% chromium and the balance substantially iron with residual impurities in ordinary amounts, said article being characterized by high resistance to abrasion, resistance to deformation on hardening and by forging and hardening characteristics comparable to steels having a carbon content less than that of the article by an amount equal to about the per cent vanadium 1 4.2

14. An abrasion resisting non-deforming alloy comprising about 1% to 3.75% carbon, about 2% to 13% vanadium, about .9% to 2.5% manganese and the balance substantially iron with residual impurities in ordinary amounts in which alloy the vanadium in excess of about 1% is combined with carbon in a ratio of about 42:1.

15. An abrasion resisting non-deforming article formed from a forgeable abrasion resisting steel alloy comprising about 1% to 3.75% carbon, about 2% to 13% vanadium, about .9% to 2.5% manganese and the balance substantially iron with residual impurities in ordinary amounts, said article being characterized by high resistance to abrasion, resistance to deformation on hardening, and by forging and hardening characteristics comparable to steels having a carbon content less than that of the article by an amount equal to about the per cent vanadium- 1% 4.2

DAVID J. GILES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

1. AN ABRASION RESISTING NON-DEFORMING STEEL ALLOY HAVING CARBON IN EXCESS OF THAT NECESSARY TO GIVE IT THE DESIRED HARDENABILITY CHARACTERISTIC COMPRISING ABOUT 1% TO 3.7% CARBON, ABOUT 2% TO 13% VANDAIUM, AT LEAST ONE OF THE GROUP CONSISTING OF CHROMIUM, TUNGSTEN, MANGANESE AND MOLYBDENUM IN INDIVIDUAL PERCENTAGES OF MANGANESE .90% TO 2.5%, CHROMIUM 1.4% TO 5% TUNGSTEN 1.75% TO 6.5%, MOLYBDENUM 1% TO 4% AND IN AGGREGATE PERCENTAGES IN SUBSTITUTED AMOUNTS SUCH THAT THE HARDENING PROPERTIES PRODUCED BY THE AGGREGATE ARE SUBSTANTIALLY EQUAL TO THE HARDENING PROPERTIES PRODUCED BY AN INDIVIDUAL MEMBER OF THE GROUP WITHIN ITS INDIVIDUAL PERCENTAGE RANGE, AND THE BALANCE SUBSTANTIALLY IRON WITH RESIDUAL IMPURITIES IN ORDINARY AMOUNTS IN WHICH ALLOY THE CONCENTRATIONS OF VANADIUM AND CARBON WITHIN THE GIVEN LIMITS ARE ADJUSTED STO THAT THE RATIO OF VANADIUM IN EXCESS OF ABOUT 1% TO THE EXCESS CARBON IS ABOUT 4.2:1. 